215. I think it's two-fold...

a) there is conflicting "science". Some studies show facts supporting gun control while other studies show facts supporting gun ownership... and the only thing that ever seems consistent between the two opposing studies is the fact that a study end up supporting the advocacy group paying for it (gee, what a coincidence). So now you have people who have personal beliefs and all you need to do is give them pieces of real evidence supporting their belief and all of a sudden their beliefs become "fact"; contradicting evidence be damned. I believe the only way any evidence actually scientifically supports one argument or another depends on the framing/context of the debate.

b) People are human. There is a natural urge to survive and protect life. In this nation there is also a social urge to be free and protect that freedom. I don't think for 2A supporters that it is so much about the gun in the physical sense. The steel, the lead, the powder and the intricacy/harmony of mechanical design... it's what the power of the gun represents. Guns are powerful tools and, to put it bluntly, people don't like having power removed from them. I think on a baser lever, people will always gravitate towards more freedom and power even if those attributes, to some extent, come at the expense of others.

Neither of these two things is mutually exclusive of voting for a democrat or voting for a republican.